Add root.jl

src/root/root.jl

+struct ROOTFile
+    _fobj::UnROOT.ROOTFile
+    online::Union{OnlineTree, Missing}
+    offline::Union{OfflineTree, Missing}
+
+    function ROOTFile(filename::AbstractString)
+        customstructs = Dict(
+            "KM3NETDAQ::JDAQEvent.snapshotHits" => Vector{SnapshotHit},
+            "KM3NETDAQ::JDAQEvent.triggeredHits" => Vector{TriggeredHit},
+            "KM3NETDAQ::JDAQEvent.KM3NETDAQ::JDAQEventHeader" => EventHeader,
+            "KM3NETDAQ::JDAQSummaryslice.KM3NETDAQ::JDAQSummarysliceHeader" => SummarysliceHeader,
+            "KM3NETDAQ::JDAQSummaryslice.vector<KM3NETDAQ::JDAQSummaryFrame>" => Vector{SummaryFrame}
+        )
+        fobj = UnROOT.ROOTFile(filename, customstructs=customstructs)
+        tpath_offline = ROOT.TTREE_OFFLINE_EVENT
+        offline = tpath_offline ∈ keys(fobj) ? OfflineTree(fobj) : missing
+        tpath_online = ROOT.TTREE_ONLINE_EVENT
+        online = tpath_online ∈ keys(fobj) ? OnlineTree(fobj) : missing
+        new(fobj, online, offline)
+    end
+end
+Base.close(f::ROOTFile) = close(f._fobj)
+function Base.show(io::IO, f::ROOTFile)
+    s = String[]
+    !ismissing(f.online) && push!(s, "$(f.online)")
+    !ismissing(f.offline) && push!(s, "$(f.offline)")
+    info = join(s, ", ")
+    print(io, "ROOTFile{$info}")
+end